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Topic: Fel Pro - gray bolt prep.. (Read 310 times)

I assembled an engine a few years ago using Fel Pro gray bolt prep on the head bolts and never retorqued the bolts - although the head gaskets (also Fel Pro) were a type that specified as not needing it to be done.Question - does anyone know if gray bolt prep remains flexible and useful enough to allow bolts to be retorqued at any point. I do recall that it did specify that head bolts could be retightened after the first heat /cool cycle using it - but does anyone know if it would be possible even after a couple of years of moderate use - or will it have hardened up to a point where any additional tightening will just create more problems than it might fix?Thanks - my understanding is that it is no longer available, if so are there any best alternatives to it? - Randy

I assembled an engine a few years ago using Fel Pro gray bolt prep on the head bolts and never retorqued the bolts - although the head gaskets (also Fel Pro) were a type that specified as not needing it to be done.Question - does anyone know if gray bolt prep remains flexible and useful enough to allow bolts to be retorqued at any point. I do recall that it did specify that head bolts could be retightened after the first heat /cool cycle using it - but does anyone know if it would be possible even after a couple of years of moderate use - or will it have hardened up to a point where any additional tightening will just create more problems than it might fix?Thanks - my understanding is that it is no longer available, if so are there any best alternatives to it? - Randy

I don't know for sure, but I've built enough SB Chevy engines with Permatex #2 on the head bolt threads to learn to leave them alone. Why fiddle with them after all that time and risk breaking the thread seal in the deck?